Process and apparatus for injection molding tire treads

(19)

(11)

EP 0 287 495 A3

(12)	EUROPEAN PATENT APPLICATION

(88)	Date of publication A3:
	14.03.1990 Bulletin 1990/11

(43)	Date of publication A2:
	19.10.1988 Bulletin 1988/42

(21)	Application number: 88630062.3

(22)	Date of filing: 11.04.1988

(51)	International Patent Classification (IPC)⁴: B29C 45/14, B29D 30/62 // B29L30:00

(84)	Designated Contracting States:
	DE FR GB IT NL

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Priority:

13.04.1987 US 37509

(71)	Applicant: THE GOODYEAR TIRE & RUBBER COMPANY
	Akron, Ohio 44316-0001 (US)

(72)	Inventor:
	Majerus, Norbert Akron Ohio 44313 (US)

(74)	Representative: Leitz, Paul
	Goodyear Technical Center-Luxembourg L-7750 Colmar-Berg L-7750 Colmar-Berg (LU)

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References cited: :

(54)	Process and apparatus for injection molding tire treads

(57) A viscoelastic fluid molding material (50) is injected into a tire tread cavity (32) between the mold (10) and an inflatable tread supporting body (30). The clearance distance (A) between the mold (10) and the inflatable tread supporting body (30) is varied to increase the flow of the initial amount of fluid molding material (50) into remote portions of the tire tread cavity (32) and provide for the flow of the final amount of fluid molding material (50) into gate portions (52) while the tread supporting body (30) is being deflected.
Circumferentially spaced gates (76) may be spaced from the centerplane (20˝-20˝) of the mold (10˝) and have runners (80) extending toward the shoulders of the tread supporting body (30˝) for increased flow of the initial amount of fluid molding material (50˝) into remote shoulder portions (52˝) of the tread cavity (32˝). Sealing rings (56) at the side edges of the tread cavity (32) prevent flow of fluid molding material (50) into sidewall areas (60) of side members (16,18) of the mold (10).

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